Three circuit foot switch



June 28, 1932. R. DANUFF THREE-CIRCUIT FOOT SWITCH Filed July 28, 1931 INVENTR I 5L3) w A TTORNEY wziumq Patented June 28, 1932 UNITED STATES IRVING B. DANUIF, OF BRONX, NEW YORK THREE CIRCUIT FOOT SWITCH Application filed July 28, 1931. Serial No. 553,536.

This invention relates to improvements in picture projection apparatus, and has as its principal object the provision of means whereby a plurality of projection machines are so controlled that substantially a continuous display of pictures may be thrown upon the screen without break or intermission occurring in changing from one machine to another.

A further feature is in the provision of a type of switch adapted to be operated pedally and arranged at a convenient oint for the operator, contiguous to each 0 a series of projection machines.

Another purpose is to produce a switch adapted to control current delivered to two or more of the machines, whereby the circuit may be instantly changed from one to another of the machines in the series to open the dowser on any on machine, while simultaneously closing thz dowsers on all other machines in the series.

A still further object is in the provision of a switch using a minimum number of parts, inexpensive to construct, unusually easy to operate, and which dispenses with the cumbersome and complicated multi-conductor system usually employed. 7

These several important, features are attained by the novel construction and combi-' nation of parts hereinafter described and shown in the annexed'drawing, forming an essential part of this disclosure, and in which Fig. 1 is a vertical sectional View of an embodiment of a switch made in accordance with the invention, shown in normal posi tion.

Fig. 2 is a front elevational view of the same, parts being broken away .to show the interior, and illustrated as in a closed or operative position.

Fig. 3 is a diagrammatic view of the electrical circuit and principal instrumentations involved.

The switch, shown in considerable detail in Figs. 1 and 2,. includes a casing, generally designated by the numeral 10, having on its top or upper surface 11, a cylindrical extension 12 provided with a screw cap 13, the cap and upper wall of the casing containing a circular aperture adapted to guide an extending plunger 14 provided with a serrated or knurled knob-like head 15.

Fixed to the plunger bar 14 is a collar 16 pressed upwardly against the inner side of the cap 13 by a coiled compression spring 17 encircling the plunger bar at its lower end abutting the upper wall of the casin The lower end of the plunger bar 1s firmly engaged in the raised central hub portion of a dielectric plate 18 having slots 19 formed in its end edges to slidably engage rods 20-'2l the upper portions of which are in electrical engagement with contact plates 2223, the upper. terminals of the rods being set in plate insulator 24 secured against the under surface of the top wall 11 of the casing.

Each of the contact plates 2223 are provided with binding screws 26 by which are secured U shaped spring contacts 27-28 engageable with riveted studs 2930 extending through the dielectric plate 18 and holding rigidity against its lower surface a plate conductor 31 by which the contacts 2728 are held in paired relation to normally close the circuit between contacts 27-28, the plate conductor being clear of the plunger bar 14.

Carried by the reduced lower ends of the rods 2021, which are provided with clamp nuts, is a second dielectric plate 32 on which are engaged a series of spring contacts 33-3435, held by binding screws 363738 connected respectively with conductors 404142, a similar conductor 39 being clamped by the nut on the rod 21, all these several conductors entering the casing by the cable 43.

The conductor 42 is similarly clamped by a nut to the rod 20 which, by reason of the com ductor plate 22, is in electrical engagement with the spring contact 27; it is also in electric engagement with the spring contact 35 by reason of a plate conductor 14 set in the dielectric plate 32.

Under normal. conditions the spring 17 holds the knob 15 extended the contacts 27 and 28 in circuit; upon pressure being applied to the knob 15 the dielectric plate 18 is forced inwardly, breaking the circuit between the contacts 28 and 27, and ultimately closing the contacts 33-34 and 35. Referring now more to the diagrammatic view shown in Fig. 3, three like shutters or mounted on a common axis an so arranged that the solenoids 53-53'-53" operate to open the dowsers while the mating solenoids 54-54-54" act to close the dowsers.

The articular type of dowsers, armatures and so enoids shown are merely illustrative and no part of the invention, and obviously any type of electrically controlled or oper-. ated dowser may be employed with equal results.

In the illustration, these solenoids are all connected to one leg of the main line 55 by av conductod 57-57 -57' When the switches are in normal position as shown in Fig. 1, the circuits to all the solenoids are open and the dowsers remain inactive in either their open or closed positions.

In Fi 3, dowser 50" is shown immediately a ter it had been ned while the other two are shown. close The switch at projector controlled by dowser 50" had been depressed, thus opening the circuit between its contacts 27-28,

that is between conductors 39" and 42 and instead, closing the circuit between its contacts 33-34-35, that is between conductors 41" and 42". Current has passed from conductors 55 through lead 57 through solenoid 53"" and through leads 40, 41" to conductor 56 thus energizing solenoid 53 causing dowser to open; Simultaneously current has passed from co-nductor through leads 57-57 through solenoids 54-54, -through leads 39-39, leads 42-42, lead 4 throu h switch through lead 41", through con uctor 56, thus energizing all the closing solenoids 54-54 to close any dowser which may be open. The switch is then immediately released until another change-over is desired.

From the foregoing it will be seen that a simple device for this purpose has been disclosed in the referred form of its embodiment, but it 1s not desired to restrict the details to the exact construction shown, it

531d rods bein being obvious that changes, not involving the exercise of invention, may be made without conflict with the scope of the appended claims. 7

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

, 1. In a switch adapted to control a plurality of circuits to pairs of solenoids, a casing having a spring raised plun er therein, a plate conductor insulated carried by said plunger, a pair of spaced spring contacts insulated from said casing normally in engagement with said conductor a pair of spaced conductorrods aeting as guides for said plunger carried plate, in circuit with a current of electricity, a ielectric plate in which said rods are fixed, a series of spring contacts carried by said dielectric plate, each being om and v in circuit with an electric current leading to other pairs of solenoids, and means to close a circuit from one of the last named contacts with one of the first named contacts.

2. A reciprocating switch com rising a casing, a cylindrical extension a ve said casing, a screw ca surmounting said extension, a plunger a apted to partially extend beyond the cap, alined apertures in the cap and the upper wall of the casing adapted to guide the plunger, a collar fixed on said plunger, a coil spring encirclin the plunger within theextension and co ned between the collar and the upper wall of the casing to urge the Inn r outwardly, a bridge conductor carried y said plunger, a pair of spaced contacts normally bridged by said conductor, a air of s aced conductors bein in circuit with an e ectric current, one 0 said conductors bein in electric engagement with one of sai plate in which said conductors are fixed, a series of spring contacts carried by said dielectric plate, each being in circuit'with an electric current leading to electrically operated devices, said bridge conductor also servin 4 attimes to close the circuit between the said series of s ring contacts.

Signed at New 'ork, in the county and State of New York, this 20th day of July,

. IRVING R. DANUFF.

contacts, a dielectric breaking all circuits to the solenoids I 

